The blurring lines between VoIP, PSTN, and cellular

This past week, I've been testing several voice services that really offer a taste of what the future of telephone service will be like. We've come a long way since my childhood, when the family had not just a single phone line but a single telephone handset that sat in a niche in the hallway.

There were no modular jacks -- the phones were hard-wired into the wall, so most folks didn't have extensions in different rooms. If you did, you had to pay an extra monthly fee for each one. And back then, if you didn't like the standard black dial phone, you couldn't just go out and buy one. You could buy a telephone housing at places like Sears, but then the phone company had to install the "guts" for you.

Today, of course, we have phones everywhere -- and all kinds of them. My husband and I have a VoIP line for most of our calling, a PSTN line for the security alarm system and fax machine, and each of us have cell phones (which also have full Internet connectivity). In addition, I have hands-free phone service through OnStar in my car, and we both have Private Phone voice mail numbers that we can give out to people where they can leave messages if we don't want to give them our "real" phone numbers, as well as Skype accounts. That means between the two of us, we have nine different phone numbers.

And Gizmo makes 10

One of the services I've been trying out this week is Gizmo, another Web-based VoIP service, which gives me yet another number. The Gizmo Project, similarly to other services such as Skype, allows you to make free calls to other Gizmo users as well as to users of Yahoo! Messenger, Windows Live, and Google Talk.

If you want people to be able to call you from traditional phones, you have to sign up (and pay) for one or more "Call In" phone numbers. Each number costs $12 for three months or $35 for a year. You get unlimited incoming calls, voice mail, conference calling, and the ability to forward calls to cell phones or landlines.

If you want to call out to traditional or mobile phones, you have to sign up for the "Call Out" service. The rates vary from 1.9 cents per minute (in the United States) to 34.4 cents to exotic locations such as Afghanistan. This is still much less than the per-minute international rates for PSTN or even more traditional VoIP services. (For example, a call to Afghanistan costs around 70 cents per minute with Lingo or Vonage, and that's on top of the monthly service fees of $20 to $25 per month.) There's no monthly charge for Gizmo's Call Out service; you just pay for the calls you make.

Another interesting Gizmo option is the Area775 number. This is a U.S.-based phone number that will ring on both your computer and a regular phone simultaneously. It allows you to listen to messages as callers leave them, so you can screen your calls and answer if you want to. You can also transfer calls to another phone with the press of a button.

Keeping up with all these numbers

As more and more people now have a whole slew of phone numbers to keep up with, a service such as Google's GrandCentral begins to make more sense. Luckily, I recently received a beta tester invitation to that program, too. And it's pretty cool.

The concept is simple -- one phone number and one centralized voice mailbox for all your numbers. When you sign up for a GrandCentral account, you get (yet another!) phone number, and you give this one to everyone. You don't have to give anyone your "real" numbers anymore.

If you move or change jobs or go with a different cellular provider and get a new number, you don't have to distribute it to everyone. You just go to the account management Web site and change the number in your GrandCentral list of numbers.

All of your various phone accounts go through this number. The really cool thing, though, is that you can choose which phones you want to ring when a particular person calls you. So if you don't want to get calls on your cell phone from talkative Aunt Sally, you can configure it so her calls only ring on your landline or your VoIP line.

Features, features, and more features

There are features galore. In addition to listening in to voice mail and screening your calls, you can block unknown or unwanted callers. You can even have the system announce that the number is not in service when that persistent campaign worker keeps calling you for donations.

And you don't have to personally know that a particular number is a telemarketer or other spam call. Members of the GrandCentral community can mark such messages as spam. Those numbers go into a "blacklist" that you can use -- if you choose to -- to block those calls without ever having to endure one of them yourself.

The voice mail feature is similar to VoIP service; you get e-mail notifications of your calls and can save them on your computer. A slightly more unusual feature is the ability to record a conversation while you're on a call by just pressing a key on your telephone handset.

One of the most impressive -- and potentially most useful -- features is the ability to switch phones in the middle of a call without hanging up. That is, if you're talking on the landline and need to leave the house but want to continue talking, you can transfer the call to your cell phone. Sweet!

From your computer, you can click a name in your address book to call that person. You click, then your phone rings, and it connects you to the person. Got a message from someone and want to call them back? Just press a key.

And best of all, the GrandCentral number -- not the number of the phone you're using -- shows up on the other party's caller ID, so it still preserves the privacy of your phone numbers. Oh, and GrandCentral works with Gizmo, too. You can add your Gizmo number to your list of phone numbers just like any other.


These new voice services offer a glimpse of how telephones ought to work -- seamlessly together. The lines between VoIP, PSTN, and cellular are blurring, and that's probably a good thing.

Now that we can have just one phone number, maybe the next step is to have just one phone bill. With companies like Verizon providing all three types of services, that's already a reality, too.

Deb Shinder is a technology consultant, trainer, and writer who has authored a number of books on computer operating systems, networking, and security. She currently specializes in security issues and Microsoft products, and she has received Microsoft's Most Valuable Professional (MVP) status in Windows Server Security.

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By Deb Shinder

Debra Littlejohn Shinder, MCSE, MVP is a technology consultant, trainer, and writer who has authored a number of books on computer operating systems, networking, and security. Deb is a tech editor, developmental editor, and contributor to over 20 add...